To the OP:
I totally get where you are coming from. I have always had really bad social anxiety. I just turned 22 and I spent the last 3 years of my life trying to find the best drug to help me loosen up and be myself. I had some good experiences and some really bad ones too. There isn't a magic pill that will cure your SA for more than a few hours. As soon as w/e drug you take wears off, you're back to feeling depressed and lonely. I know how it feels. You have to find the root cause of your self esteem issues and work on fixing it w/ cognitive behavioral therapy. Sure, it may take a while but it will be PERMANENT and you wont run the risk of health issues, addictions, jail, or ending up dead. I believe MDMA and other drugs like shrooms can still be beneficial by making you look deep inside yourself and face issues. BUT these are things that should be taken a few times a year at most.
Opiates can make you more open only bc you feel so fucking great, but they are super addictive and nodding out in front of people is not a good look lol
Benzos do help a little bit, maybe reducing your anxiety by 20-30%. They are addictive, and can make you appear/act drunk if you take too much. Benzo w/d is the fucking worst
Alcohol is great for social anxiety and terrible for your health. It makes you do stupid ass things that you normally would never do and make you look like a fool.
I take Adderall for school and I am more upbeat, positive, and outgoing. I can talk about anything while keeping my composure and being myself. The downside is that you have to take frequent drug holidays to keep the positive effects. If you take it more than once a week, the good feelings subside and you are left with either focus or depression/anxiety.
MDMA is great for a night out at the club but its def not something you want to take often. You also run the risk of spilling your guts to others and totally regretting it the next day. The comedown is a bitch just like with Adderall.
Weed makes me 10x more introverted and anxious than normal but its a great combo with the other drugs mentioned
All in all, there's no easy way out and if you depend on drugs to make you less insecure/confident, you won't get very far and the consequences could be detrimental. You have to put the time in, work on yourself, and the rewards will be better than any drug. Exercise increases confidence and is the best thing you can do for your body. Good luck